4 Inch Inline Fan Carbon Filter - $45 Odor Control Activated Charcoal Included Air Scrubber for Grow Tent Indoor Plants Odor Control: Designed for an enclosed environment. Our filter will soak up and eliminate some of the most undesirable and ill-smelling odours. Keep your place clean while bring you cleaner air to promote better health. Widely Applied: Various fields especially for indoor gardens, grow tents, hydroponics, odour and smoke elimination.